Electronic timepiece

ABSTRACT

An electronic timepiece having a case of which at least part is metal, a magnetic shield, and a planar antenna can suppress a drop in the sensitivity of the planar antenna. The electronic timepiece  1  has a case  10  of which at least part is metal, and hands and a movement disposed inside the case  10.  The movement includes a circuit board  23,  a planar antenna  40  attached to the circuit board  23 , a motor that drives the hands, and magnetic shields  91, 92  superimposed in plan view with at least part of the motor and not superimposed in plan view with the planar antenna. The shortest distance D 1  between the antenna electrode  42  of the planar antenna  40  and the metal part of the case  10  is greater than the shortest distance D 2  between the antenna electrode  42  and the magnetic shield  91.

BACKGROUND

1. Technical Field

The present invention relates to an electronic timepiece, and relatesmore particularly to an electronic timepiece with a planar antenna.

2. Related Art

JP-A-2014-157160 describes an electronic timepiece with a planar antennafor receiving radio frequency signals transmitted from positioninginformation satellites such as GPS (Global Positioning System)satellites.

The electronic timepiece in JP-A-2014-157160 has a photovoltaic deviceand a planar antenna disposed on the back cover side of the timepiecedial, and the planar antenna and photovoltaic device are disposed sothey are not mutually superimposed in the direction perpendicular to theface of the dial. Reducing antenna sensitivity is suppressed byseparating the planar antenna and photovoltaic device sufficiently inthe direction parallel to the plane of the dial.

A magnetic shield may be incorporated in the movement of an electronictimepiece to prevent or reduce the effect of external magnetic fields onmotors, for example. There is, therefore, a need for an electronictimepiece that can suppress loss of antenna sensitivity in an electronictimepiece having a case with metal parts, a magnetic shield, and aplanar antenna.

SUMMARY

An objective of the present invention is to provide an electronictimepiece having a case with metal parts, a magnetic shield, and aplanar antenna, and suppressing the loss of antenna sensitivity.

An electronic timepiece according to one aspect has a case of which atleast part is metal; and hands and a movement disposed inside the case.The movement includes a circuit board, a planar antenna attached to thecircuit board, a motor configured to drive the hands, and a magneticshield superimposed in plan view with at least part of the motor, andnot superimposed in plan view with the planar antenna. The shortestdistance between the antenna electrode of the planar antenna and themetal part of the case is greater than the shortest distance between theantenna electrode and the magnetic shield.

An electronic timepiece according to another aspect has a case of whichat least part is metal, a magnetic shield, and a planar antenna. Becausethe metal part of the case and the magnetic shield are metal materials,the signal-blocking effect thereof is great. More particularly, becausethe case is thick in the thickness of the timepiece, the effect on thereception sensitivity of the planar antenna is great. Because thedistance from the antenna electrode of the planar antenna to the metalpart of the case is greater than the distance from the antenna electrodeto the magnetic shield, the antenna electrode and the metal case membercan be separated relatively greatly, and the drop in receptionsensitivity caused by the case can be reduced.

An electronic timepiece that can suppress loss of reception sensitivityin the planar antenna when a magnetic shield and planar antenna aredisposed inside a case with metal parts can be provided.

In an electronic timepiece according to another aspect, the top of themetal part of the case at the end on the face side of the timepiece isabove the antenna electrode on the face side of the timepiece.

Because the top of the metal part of the case can be located above theantenna electrode on the face side (crystal) side of the timepiece, thecase body, bezel, and other members can be metal. An electronictimepiece with a metal case can therefore be provided, improving theappearance and imparting a luxury watch feel to the design of thetimepiece. Furthermore, because the metal outside case has superiordurability to a plastic case, for example, the surface is more scratchresistance and the internal movement can be protected.

An electronic timepiece according to another aspect preferably also hasa solar panel not superimposed with the antenna electrode in plan view,and the shortest distance between the antenna electrode and the metalpart of the case is greater than the shortest distance between theantenna electrode and the electrode of the solar panel.

This aspect can reduce the effect of the case on reception sensitivitybecause the distance from the antenna electrode of the planar antenna tothe metal part of the case is greater than the distance from the antennaelectrode to the electrode of the solar panel.

An electronic timepiece that can suppress loss of reception sensitivityin the planar antenna when a magnetic shield, solar panel, and planarantenna are disposed inside a case with metal parts can be provided.

Further preferably in an electronic timepiece according to anotheraspect, the shortest distance between the antenna electrode and themagnetic shield is greater than the shortest distance between theantenna electrode and the electrode of the solar panel.

This aspect can reduce the effect of the magnetic shield on receptionsensitivity because the distance from the antenna electrode of theplanar antenna to the magnetic shield is greater than the distance fromthe antenna electrode to the electrode of the solar panel. The magneticshield is thicker than the electrode part of the solar panel, and has agreater effect on loss of planar antenna sensitivity than the electrodeof the solar panel. Therefore, if the antenna electrode of the planarantenna is located farther from the magnetic shield than the electrodeof the solar panel, the drop in planar antenna sensitivity can besuppressed compared with when the magnetic shield is closer than theelectrode of the solar panel.

An electronic timepiece according to another aspect preferably also hasa battery not superimposed with the planar antenna in plan view, theshortest distance between the antenna electrode and the metal part ofthe case being greater than the shortest distance between the antennaelectrode and the battery.

Thus comprised, because the antenna electrode of the planar antenna canbe separated farther from the metal case member than from the battery,the effect of metal parts of the case on reception sensitivity can bereduced. The battery is thinner than the case, and is often disposed inthe thickness direction of the timepiece closer to the back cover thanthe antenna electrode. The effect of the battery on loss of sensitivityin the planar antenna is less than the effect of the case. Therefore, ifthe antenna electrode of the planar antenna is located farther from thecase than from the battery, the drop in planar antenna sensitivity canbe suppressed compared with when the case is closer to the antennaelectrode than the battery.

Further preferably in an electronic timepiece according to anotheraspect, the magnetic shield includes a first magnetic shield on the faceside of the motor, and a second magnetic shield disposed on the backcover side of the motor. The shortest distance between the antennaelectrode and the first magnetic shield is greater than the shortestdistance between the antenna electrode and the second magnetic shield.

Because the shortest distance between the antenna electrode and thefirst magnetic shield is greater than the shortest distance between theantenna electrode and the second magnetic shield, the first magneticshield that easily affects reception performance and is closer to thecrystal than the antenna electrode can be separated from the antennaelectrode, and a drop in reception performance can be prevented. Thesurface area of the second magnetic shield can also be increased andmagnetic resistance improved. Reception performance and magneticresistance can therefore be more easily balanced.

Other objects and attainments together with a fuller understanding ofthe invention will become apparent and appreciated by referring to thefollowing description and claims taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an electronic timepiece according to a firstembodiment.

FIG. 2 is a plan view of the electronic timepiece.

FIG. 3 is a section view of the electronic timepiece.

FIG. 4 is a partially exploded oblique view of the electronic timepiece.

FIG. 5 is a plan view showing main parts of the movement of theelectronic timepiece.

FIG. 6 is an oblique view showing a circuit board and the planar antennaof the electronic timepiece.

FIG. 7 is a section view of the structure of the planar antenna of theelectronic timepiece.

FIG. 8 illustrates the radiation pattern of the planar antenna of theelectronic timepiece.

FIG. 9 describes the relative positions of the antenna electrode andmetal parts of the electronic timepiece.

FIG. 10 describes the relative positions of the antenna electrode andmetal parts of the electronic timepiece.

FIG. 11 is a block diagram showing the circuit configuration of theelectronic timepiece.

FIG. 12 is a section view of an electronic timepiece according to asecond embodiment.

FIG. 13 is a section view of an electronic timepiece according to athird embodiment.

FIG. 14 is a section view of an electronic timepiece according to afourth embodiment.

FIG. 15 is a plan view showing main parts of the movement of anelectronic timepiece according to the fourth embodiment.

FIG. 16 is a section view of an electronic timepiece according to thefourth embodiment.

FIG. 17 is a section view of an electronic timepiece according to thefourth embodiment.

FIG. 18 is a partially exploded oblique view of an electronic timepieceaccording to the fourth embodiment.

FIG. 19 is a section view of an electronic timepiece according toanother embodiment.

DESCRIPTION OF EMBODIMENTS

Embodiment 1

A first embodiment of an electronic timepiece 1 is described below withreference to the accompanying figures. Note that the crystal 31 side ofthe electronic timepiece 1 in the following embodiments is also referredto as the face, front, or top side, and the back cover 12 side is alsoreferred to as the back or bottom side of the electronic timepiece 1.

As described further below, an electronic timepiece 1 according to thisembodiment receives satellite signals and acquires satellite timeinformation from plural positioning information satellites S, such asGPS satellites or quasi-zenith satellites, orbiting the Earth on knownorbits, and can correct internal time information based on the acquiredsatellite time information.

As shown in FIG. 1 and FIG. 2, the electronic timepiece 1 is awristwatch with a time display unit 9A for displaying time using a dial2 and hands 3, an information display unit 9B including a subdial 2A ofthe dial 2 and a hand 4, and a calendar display unit 9C including awindow 2B in the dial 2 and a date wheel 5. The electronic timepiece 1also has a crown 6 and buttons 7 and 8 as external operating members.

The hands 3 include a second hand 3B, minute hand 3C, and hour hand 3D.The time display unit 9A therefore indicates the current time with thedial 2 and hands 3. The information display unit 9B including thesubdial 2A and hand (small hand) 4 displays information such as thetimekeeping mode, day of the week, remaining battery capacity, orreception condition. The calendar display unit 9C displays the currentdate.

The hands 3, 4 and date wheel 5 are driven by stepper motors 221 to 224and a wheel train 226 described further below.

The dial 2 is a disc-shaped member made of polycarbonate or othernon-conductive material. The subdial 2A is located at 8:00 on the dial2, and the window 2B is located at 3:00 on the dial 2. In addition tothe subdial 2A and window 2B, a through-hole 2C through which the centerpivot 3A of the hands 3 passes, and a through-hole 2D through which thepivot 4A of the small hand 4 passes, are formed in the dial 2 as shownin FIG. 3 and FIG. 4. Through-hole 2C is formed in the plane center ofthe dial 2. Through-hole 2D is formed on or near a line through thethrough-hole 2C and 8:00 on the dial 2.

External Structure of the Electronic Timepiece

As shown in FIG. 2 and FIG. 3, the electronic timepiece 1 has anexternal case 10 that houses a movement 20 described further below. Notethat FIG. 3 is a section view on a line through 6:00 and 12:00 on thedial 2.

The case 10 includes the main case 11, the back cover 12, and thecrystal 31. The main case 11 includes a tubular case member 111, and abezel 112 disposed on the front side of the case member 111.

The bezel 112 is ring-shaped. The bezel 112 and case member 111 areconnected by an interlocking tongue-and-groove structure formed on theirmutual opposing surfaces, or by double-sided adhesive tape or adhesive,for example. The bezel 112 may also be attached so that it can rotate onthe outside case member 111.

The crystal 31 is attached to the inside of the bezel 112 and is held bythe bezel 112.

A round back cover 12 is disposed to the back cover side of the maincase 11 covering the opening in the back cover side of the main case 11.The back cover 12 and the outside case member 111 of the main case 11screw together.

Note that the outside case member 111 and the back cover 12 are separatemembers in this embodiment, but the invention is not so limited and theoutside case member 111 and back cover 12 may be formed in unison as asingle piece.

The outside case member 111, bezel 112, and back cover 12 are made ofstainless steel, titanium alloy, aluminum, brass, or other metalmaterial.

Internal Configuration of the Electronic Timepiece

The internal structure housed in the case 10 of the electronic timepiece1 is described next.

As shown in FIG. 3, a movement 20, planar antenna 40 (patch antenna),date wheel 5, and dial ring 32 are housed in addition to the dial 2inside the case 10.

As also shown in FIG. 4, the movement 20 includes the base plate 21, awheel train bridge 27, a drive module 22 supported by the base plate 21and wheel train bridge 27, a circuit board 23, a storage battery 24, asolar panel 25, and magnetic shields 91, 92.

The base plate 21 is made from plastic or other non-conductive material.The base plate 21 includes a drive module housing 21A that holds thedrive module 22, a date wheel housing 21B where the date wheel 5 isdisposed, and an antenna housing 21C that holds the planar antenna 40.The date wheel housing 21B is an area on the outside side of pluralguide parts 211 that protrude from the face side of the base plate 21.

The drive module housing 21A and antenna housing 21C are disposed on theback side of the base plate 21. As shown in FIG. 3, the antenna housing21C has four walls 214 (only two shown in FIG. 3) facing the four sidesof the planar antenna 40, which is rectangular in plan view, and a coverpart 215 opposite the face side of the planar antenna 40. The cover part215 in this embodiment covers the entire surface of the planar antenna40, but a through-hole superimposed in plan view with at least part ofthe antenna electrode 42 of the planar antenna 40 may be formed in thecover part 215. Note that the four walls 214 and the cover part 215 areformed in unison with the base plate 21.

Because the antenna housing 21C is at 12:00 on the dial 2 in plan view,the planar antenna 40 is also located at 12:00 as shown in FIG. 2. Morespecifically, the planar antenna 40 is located between the center pivot3A of the hands 3 and the main case 11, and between approximately 11:00and 1:00 on the dial 2.

The drive module 22 is held in the drive module housing 21A of the baseplate 21, and drives the hands 3, 4 and date wheel 5 of the time displayunit 9A, information display unit 9B, and date display unit 9C. Morespecifically, as shown in FIG. 5, the drive module 22 includes a steppermotor 221 and first wheel train 226 for driving the hands 3 (FIG. 3); asecond stepper motor 222 and second wheel train (not shown in thefigure) for driving the minute hand 3C; a third stepper motor 223 andthird wheel train (not shown in the figure) for driving the hour hand3D; and a fourth stepper motor 224 and fourth wheel train (not shown inthe figure) that are used to drive both hand 4 and the date wheel 5. Thefourth wheel train has a date indicator driving wheel 228 (FIG. 4) forturning the date wheel 5.

The stepper motors 221 to 224 are disposed to positions not superimposedin plan view with the planar antenna 40.

Magnetic Shields

High performance magnets are commonly used in the cases of smartphonesand other mobile terminals, for example, and magnetic resistance istherefore also needed in wristwatches. To reroute magnetic fields andprevent misoperation of the stepper motors 221 to 224, magnetic shields91, 92 made of a high permeability material such as pure iron aredisposed at positions superimposed in plan view with the stepper motors221 to 224. Each of the stepper motors 221 to 224 has a coil woundaround a core, a stator, and a rotor. Because the coil portion of theseis most resistant to the effects of external magnetic fields, themagnetic shields 91, 92 do not necessarily need to be overlapping inplan view. The magnetic shields 91, 92 therefore preferably overlap atleast part of the stepper motors 221 to 224 in plan view, and moreparticularly overlap the stator and rotor in plan view.

As shown in FIG. 3 and FIG. 4, the magnetic shield 91 is on the faceside (crystal 31 side) of the base plate 21. This magnetic shield 91 isdisposed substantially covering the surface (the dial 2 side surface) ofthe stepper motors 221 to 224.

As shown in FIG. 4, apertures 911 in which the guide parts 211 aredisposed, an aperture 912 in which the date indicator driving wheel 228is disposed, and apertures 913, 914 in which the center pivots 3A, 4Aare disposed, are formed in the magnetic shield 91.

The area of the magnetic shield 91 superimposed in plan view with theplanar antenna 40 is cut out, forming a notch 915. As a result, themagnetic shield 91 does not cover the crystal side of the planar antenna40, and the planar antenna 40 can receive signals through the notch 915in the magnetic shield 91.

As shown in FIG. 3 and FIG. 4, the magnetic shield 92 is on the backside (back cover 12 side) of the base plate 21, and is closer to thecrystal than the storage battery 24. More specifically, a wheel trainbridge 27 that supports the bearings of the wheel trains is on the backcover side of the base plate 21, and the magnetic shield 92 is disposedto the back cover side of the wheel train bridge 27. As a result, themagnetic shield 92 is disposed substantially covering the back side (theback cover 12 side) of the stepper motors 221 to 224.

The magnetic shield 92 is similarly cut out in the area superimposed inplan view with the planar antenna 40, forming a notch 925.

Circuit Boards

The electronic timepiece 1 in this embodiment has two circuit boards, acircuit board 23 for GPS reception, and a circuit board (not shown inthe figure) for timepiece drive control. A timepiece control chip (CPU)61 (FIG. 11), and a timepiece drive control chip (drive circuit) 62(FIG. 11), that receive signals from the circuit board 23 for receptionare disposed to the circuit board for timepiece drive control.

As shown in FIG. 4 and FIG. 6, the circuit board 23 for GPS reception issubstantially round, and has a substantially round notch 231 in which astorage battery 24 is placed. The electronic timepiece 1 can be madesmaller by placing the storage battery 24 in this notch 231. The planarantenna (patch antenna) 40 is mounted on the dial side of the circuitboard 23. As shown in FIG. 6, a reception module 50 (receiver device,receiver chip, GPS module) that processes satellite signals receivedfrom the GPS satellites S, a power supply chip 75, and a memory chip 76are also disposed on the front side of the circuit board 23. The memorychip 76 is flash memory, and stores a firmware program for GPSreception, and time zone data for calculating the time zone fromlocation information calculated in a positioning reception process.

In this embodiment, the movement 20 is housed inside a metal main case11, and radio waves are easily blocked. Therefore, to improve receptionperformance, the planar antenna 40 is preferably disposed to a positionas close as possible to the dial 2. As a result, the circuit board 23 towhich the planar antenna 40 is affixed is preferably also close to thedial 2.

A lithium ion battery that is round in plan view is used for the storagebattery 24 as shown in FIG. 3 to FIG. 5. The storage battery 24 suppliespower to the drive module 22 and reception module 50. The storagebattery 24 is disposed in the notch 231 in the circuit board 23, and isdisposed to a position not superimposed with the planar antenna 40,reception module 50, and power supply chip 75 in plan view, and morespecifically is disposed at the 6:00 side of the dial 2.

The storage battery 24 is superimposed in plan view with at least partof the stepper motors 221, 223, 224 and the wheel train. The thickness(the dimension through the thickness of the timepiece) of the storagebattery 24 is less than the diameter of the storage battery 24 (thedimension parallel to the surface of the back cover 12), and the storagebattery 24 is flat and disposed in the notch 231 of the circuit board23. As a result, a thin electronic timepiece 1 can be achieved even ifthe storage battery 24 is superimposed in plan view with part of thestepper motors and wheel train.

Solar Panel

The electrodes of the solar panel 25 include front electrodes and backelectrodes. The front electrode is a transparent electrode made ofindium tin oxide (ITO) or other transparent electrode material thatpasses light. An amorphous silicon semiconductor thin film is formed asthe photovoltaic layer on a plastic film base layer.

Because GPS satellite signals are high frequency signals ofapproximately 1.5 GHz, GPS signals are attenuated by even the thintransparent electrode of the solar panel, unlike the long wave standardtime signals that are received by radio-controlled timepieces, andantenna performance drops. As a result, as shown in FIG. 4, a notch 251is formed in the disc-shaped solar panel 25 at the position overlappingthe planar antenna 40 in plan view. The solar panel 25 therefore coversthe face side of the base plate 21 but does not cover the face side ofthe planar antenna 40. The planar antenna 40 can therefore receivesignals through the notch 251 in the solar panel 25.

Note that an opening 252 superimposed in plan view with the window 2B inthe dial 2, and holes 253, 254 through which the center pivots 3A, 4A ofthe hands 3, 4 pass, are also formed in the solar panel 25.

The solar panel 25 is divided into plural cells, and the cells areconnected in series. As shown in FIG. 4, the solar panel 25 in thisembodiment has seven solar cells, and the solar cells are connected inseries. One solar cell produces approximately 0.6 V or more. Byconnecting the seven solar cells in series, the solar panel 25 thereforeproduces approximately 0.6 V×7=approximately 4.2 V or more. A lithiumion storage battery with a high EMF can therefore be charged, anddevices with high current consumption, such as a GPS receiver (GPSmodule) can be driven.

Date Indicator

The date wheel 5, which is a ring-shaped calendar wheel having datenumbers displayed on the surface, is held in the date wheel housing 21Bof the base plate 21. The date wheel 5 is made from plastic or othernon-conductive material. In plan view, the date wheel 5 overlaps atleast part of the planar antenna 40. Note that the calendar wheel is notlimited to a date wheel 5, and may be a day wheel showing the days ofthe week, or a month wheel showing the months.

Dial

The dial 2 is disposed on the face side of the base plate 21 coveringthe face side of the solar panel 25 and the date wheel 5. The dial 2 ismade from a material such as plastic that is non-conductive andtransparent to at least some light.

Abbreviations or other markings may be disposed to the surface of thedial 2 overlapping the planar antenna 40 in plan view. To improve thereception performance of the planar antenna 40, these parts arepreferably made from plastic or other non-conductive material instead ofmetal. The subdial 2A and markings thereof that are not located over theplanar antenna 40 may be metal.

Because the dial 2 is transparent to light, the solar panel 25 locatedon the back side of the dial 2 can be seen through the dial 2 from thefront of the timepiece. The color of the dial 2 therefore appearsdifferent in the areas where the solar panel 25 is present and where thesolar panel 25 is not present. Design accents may be added to the dial 2so that this color difference is not conspicuous.

Furthermore, because a notch 251 is formed in the solar panel 25, thecolor of the dial 2 in the area over the notch 251 may also appeardifferent from other areas. To prevent this, a plastic sheet of the samecolor (such as dark blue or purple) as the solar panel 25 may bedisposed below the solar panel 25, or the plastic film base layer may beleft covering all of the solar panel 25, removing only the electrodelayer that blocks radio waves in the part covering the planar antenna 40in plan view.

Dial Ring

A dial ring 32 that is a ring shaped member made of a plasticnon-conductive material (such as ABS plastic) is disposed to the faceside of the dial 2. The dial ring 32 is disposed around thecircumference of the dial 2, is conically shaped with the insidecircumference surface sloping down to the dial 2, and has hour markersor world time zone markers printed on the sloping inside surface. Bymolding the dial ring 32 from plastic, reception performance can bemaintained, complicated shapes can be formed, and design creativity canbe improved.

The dial ring 32 is held pressed against the dial 2 by the bezel 112. Inplan view from the crystal 31 side, the time display unit 9A in thisembodiment therefore comprises the hands 3 and the area where markersindicated by the hands 3 can be seen, and more specifically includes theexposed area of the dial 2 delineated by the dial ring 32, the hands 3,and the exposed surface of the dial ring 32 delineated by the bezel 112.In other words, the time display unit 9A comprises the round portiondelineated by the inside circumference surface of the bezel 112 whenlooking at the electronic timepiece 1 from the crystal 31 side.

Planar Antenna

The planar antenna 40, which is a patch antenna (microstrip antenna) isdisposed in the antenna housing 21C of the base plate 21. The planarantenna 40 receives satellite signals from GPS satellites S.

In plan view, the planar antenna 40 is not superimposed with the maincase 11 (outside case member 111 and bezel 112), the solar panel 25, orthe magnetic shields 91, 92, and is superimposed with the date wheel 5,dial 2, and crystal 31, which are made of non-conductive materials. Morespecifically, all parts of the electronic timepiece 1 that are over theplanar antenna 40 on the face side of the planar antenna 40 are madefrom non-conductive materials.

As a result, satellite signals coming from the face side of thetimepiece first pass through the crystal 31, pass through the dial 2,date wheel 5, and base plate 21 without being blocked by the main case11, magnetic shields 91, 92, or the solar panel 25, and are thenincident to the planar antenna 40. Note that because the area of thehands 3, 4 over the planar antenna 40 is small, they do not interferewith receiving satellite signals even if they are made of metal, but arepreferably made from a non-conductive material because they willinterfere with satellite signal reception even less.

The GPS satellites S transmit satellite signals as right-hand circularlypolarized waves. As a result, the planar antenna 40 in this embodimentis a patch antenna (also called a microstrip antenna) with excellentcircular polarization characteristics.

As shown in FIG. 7, the planar antenna 40 in this embodiment is a patchantenna having a conductive antenna electrode 42 stacked on a ceramicdielectric substrate 41.

This planar antenna 40 is manufactured as described below. First, bariumtitanate with a dielectric constant of 60-100 is formed to the desiredshape in a press and sintered to complete the ceramic dielectricsubstrate 41 of the antenna. Aground electrode 43 forming the groundplane (GND) of the antenna is made by screen printing a primarily silver(Ag) paste, for example, on the back side (the side facing the circuitboard 23) of the dielectric substrate 41.

An antenna electrode 42 that determines the antenna frequency and thepolarity of the received signals is formed on the face side of thedielectric substrate 41 (the side facing the base plate 21 and dial 2)by the same method as the ground electrode 43. The antenna electrode 42is slightly smaller than the surface of the dielectric substrate 41, andan exposed surface 411 where the antenna electrode 42 is not present isdisposed around the antenna electrode 42 on the surface of thedielectric substrate 41.

The surface of the dielectric substrate 41 in plan view is basicallysquare with each side approximately 11 mm long in this example. Thesurface of the antenna electrode 42 in plan view is basically squarewith each side approximately 8 to 9 mm in this example. As shown in FIG.6, the four corners of the dielectric substrate 41 are mitered toprevent cracking, but substrates that are not mitered may be used.

FIG. 7 illustrates the operating principle of a planar antenna 40 (patchantenna). In FIG. 7 the dotted lines 45 represent radio wavestransmitted or received by the planar antenna 40, and the arrows 46represent the electric lines of force.

A square patch antenna resonates when one side is a half wavelength, anda round patch antenna resonates when the diameter is approximately 0.58wavelength, but the size of the antenna size can be reduced by thewavelength shortening effect of a ceramic or other dielectric. Because apatch antenna works by the strong electric field around the edge of thepatch (antenna electrode 42) radiating from the edge into space (whenused as a transmission antenna), the electric lines of force becomestronger with proximity to the antenna and are easily affected by theeffects of nearby metals and dielectrics. The effect of metal partslocated above (on the crystal 31 side) of the circuit board 23, which isthe ground (GND), are particularly great. To receive GPS satellitesignals, therefore, the distance between the metal case member 111 andthe antenna electrode 42 must be at least 2 mm, and is ideallyapproximately 3 mm or more.

In this example, the walls 214 are located between the planar antenna 40and case member 111, and as described below the planar antenna 40 isdisposed to a position separated at least a specific distance from theinside surface of the case member 111. As a result, a drop in receptionperformance resulting from the proximity of the planar antenna 40 to themetal case member 111 can be suppressed, and the reception performancerequired by the electronic timepiece 1 can be assured. Note also thatthe dielectric substrate 41 and antenna electrode 42 of the planarantenna 40 in this embodiment are basically rectangular in plan view.

FIG. 8 illustrates the radiation pattern of the planar antenna 40, theplane of the planar antenna 40 (patch antenna) on the X-axis and thezenith on the Z-axis.

As shown in FIG. 8, because the planar antenna 40 is unidirectional withantenna gain greatest on the Z-axis toward the zenith, radio wavesperpendicularly incident to the dial 2 are the easiest to receive.Furthermore, while directivity on the X-axis parallel to the plane ofthe planar antenna 40 is low compared with the Z-axis, because it is nottotally absent, proximity of the metal main case 11 (case member 111) tothe side of the planar antenna 40 also affects reception performance.

Furthermore, because directivity on the −Z-axis below the planar antenna40 is weak, metal parts and the back cover 12 located below the planarantenna 40 have little effect on reception performance compared with alinear antenna such as an inverted-F antenna having uniform directivityin all directions. Compatibility with a metal case is therefore good,and incorporation in the case 10 according to this embodiment is simple.

Note also that because the electronic timepiece 1 is worn on the user'swrist and may receive satellite signals from many different directions,the planar antenna 40 preferably has directivity in directions otherthan the zenith as shown in FIG. 8. Directivity of the planar antenna 40can then be improved by making the bezel 112 and dial ring 32 fromnon-conductive materials.

The planar antenna 40 is mounted on the face side of the circuit board23, and is electrically connected to the antenna and GPS module, thereception module 50, on the circuit board 23. The circuit board 23 canalso function as a ground plane by connecting the ground electrode 43 ofthe planar antenna 40 through the ground pattern of the circuit board 23to the ground node of the reception module 50. The case member 111 andback cover 12 can also be used as the ground plane by connecting theground node of the reception module 50 through the ground pattern of thecircuit board 23 to the metal case member 111 or back cover 12.

As shown in FIG. 3, the planar antenna 40 is held in the antenna housing21C by affixing the circuit board 23 to the base plate 21. Because thedielectric substrate 41 of the planar antenna 40 is ceramic, hard, andeasily chipped, a shock absorber 47 such as a sponge cushion is disposedbetween the dielectric substrate 41 and the base plate 21. Damage to thedielectric substrate 41 by collision with the base plate 21 cantherefore be prevented.

Distance between the Antenna Electrode and Metal Parts

The relationship between the location of metal parts disposed around theplanar antenna 40 and the antenna electrode 42 in the electronictimepiece 1 is described next with reference to FIG. 9 and FIG. 10. Inthis embodiment, the metal parts located around the planar antenna 40are the main case 11 (outside case member 111) of the case 10, themagnetic shields 91, 92, the electrode of the solar panel 25, and thestorage battery 24.

In the figures, the shortest distance between the antenna electrode 42and main case 11 is D1; the shortest distance between the antennaelectrode 42 and the magnetic shield 91 disposed on the back of the dial2 is D2; the shortest distance between the antenna electrode 42 and themagnetic shield 92 on the back side of the wheel train bridge 27 is D3;the shortest distance between the antenna electrode 42 and the electrodeof the solar panel 25 is D4; and the shortest distance between theantenna electrode 42 and the storage battery 24 is D5.

As described above, because the planar antenna 40 has strong directivitytoward the zenith (the direction toward the crystal 31), the receptionsensitivity of the planar antenna 40 is easily affected by the case 10,which is the thickest of the metal parts and is located closer to theface of the timepiece than the planar antenna 40. As a result, theshortest distance D1 between the antenna electrode 42 of the planarantenna 40 and the case 10 must be increased to sufficiently separatethe antenna electrode 42 from the case 10.

Furthermore, while the magnetic shield 91 is between the crystal 31 andthe planar antenna 40, the magnetic shield 91 is thin at approximately0.2-0.5 mm and has less effect on reception sensitivity than the thickcase 10. As a result, the shortest distance D2 between the antennaelectrode 42 and magnetic shield 91 is shorter than shortest distanceD1.

Note that because the inside surface of the main case 11 is round, theshortest distance D1 between the antenna electrode 42 and main case 11is the shortest distance D1H between the corner of the antenna electrode42 and the inside surface of the main case 11 in plan view as shown inFIG. 10.

Because the notch 915 in the magnetic shield 91 is substantially squarealong the antenna electrode 42, the shortest distance D2 between theantenna electrode 42 and magnetic shield 91 is distance D2H in planview, but because the antenna electrode 42 and the magnetic shield 91are at different elevations in the thickness of the timepiece, shortestdistance D2 is a diagonal distance as shown in FIG. 9. Note that becauseof similar differences in elevation, the other shortest distances D3,D4, D5 are distances D3H, D4H, D5H in plan view, but the actual shortestdistances are diagonal distances D3, D4, D5 as shown in FIG. 9.

The electrode of the solar panel 25 is also on the dial side of theplanar antenna 40, but because the solar panel 25 is approximately0.1-0.2 mm thick and is thinner than the magnetic shield 91, its effecton reception sensitivity is relatively small. As a result, the shortestdistance D4 between the antenna electrode 42 and the electrode of thesolar panel 25 can be shorter than shortest distance D1.

Because the magnetic shield 92 is on the back cover side of the antennaelectrode 42 and is a thin 0.2-0.5 mm, its effect on receptionsensitivity is smaller than the case 10. Therefore, the shortestdistance D3 between the antenna electrode 42 and the magnetic shield 92can be shorter than shortest distance D1.

Note that because the storage battery 24 is somewhat thick and itslocation can be easily separated from the antenna electrode 42, theshortest distance D5 between the antenna electrode 42 and the storagebattery 24 is set longer than shortest distance D1. In this embodiment,therefore, D1>D2, D1>D4, D1>D3, and D5>D1.

Comparing the magnetic shield 91 located closer to the crystal 31 thanthe antenna electrode 42 of the planar antenna 40, and the electrode ofthe solar panel 25, because the magnetic shield 91 is thicker, itseffect on the reception sensitivity of the planar antenna 40 is greater.As a result, D2>D4 is preferable. However, because the magnetic shield92 and storage battery 24 can be easily disposed to positions away fromthe antenna electrode 42, D2<D3<D5. In other words, the shortestdistances to the antenna electrode 42 preferably decrease in the orderD5>D1>D3>D2>D4. Note that depending on the location of the storagebattery 24, D1>D5 is also conceivable.

Circuit Configuration of the Electronic Timepiece

The circuit design of the electronic timepiece 1 is described next withreference to FIG. 11.

As shown in FIG. 11, the electronic timepiece 1 has a planar antenna 40,a SAW filter 35, the reception module 50, a display control unit 60, anda power supply unit 70.

The SAW filter 35 is a bandpass filter that passes signals in the 1.5GHz waveband. A LNA (low noise amplifier) may also be disposed betweenthe planar antenna 40 and the SAW filter 35 to improve receptionsensitivity.

Note also that the SAW filter 35 may be embedded in the reception module50.

The reception module 50 processes satellite signals passed through theSAW filter 35, and includes an RF (radio frequency) circuit 51 and abaseband circuit 52.

The RF circuit 51 includes a PLL (phase-locked loop) circuit 511, a VCO(voltage controlled oscillator) 512, a LNA (low noise amplifier) 513, amixer 514, an IF (intermediate frequency) amplifier 515, an IF filter516, and an A/D converter 517.

The satellite signal passed by the SAW filter 35 is amplified by the LNA513, mixed by the mixer 514 with the clock signal output by the VCO 512,and down-converted to a signal in the intermediate frequency band.

The IF signal from the mixer 514 is amplified by the IF amplifier 515,passed through the IF filter 516, and converted to a digital signal bythe A/D converter 517.

The baseband circuit 52 includes, for example, a DSP (digital signalprocessor) 521, CPU (central processing unit) 522, a RTC (real-timeclock) 523, and SRAM (static random access memory) 524. A TCXO(temperature compensated crystal oscillator) 53 and flash memory 54 arealso connected to the baseband circuit 52.

A digital signal is input from the A/D converter 517 of the RF circuit51 to the baseband circuit 52, which acquires satellite time informationand navigation information by a correlation process and positioningcomputation process.

Note that the clock signal for the PLL circuit 511 is generated by theTCXO 53.

The display control unit 60 includes a control unit (CPU) 61, a drivecircuit 62 that drives the hands 3, 4, a time display unit, andinformation display unit.

The control unit 61 includes a RTC 611 and storage 612.

The RTC 611 calculates internal time information using a referencesignal output from a crystal oscillator 63.

The storage 612 stores the satellite time information and positioninginformation output from the reception module 50. Time difference datacorresponding to the positioning information is also stored in thestorage 612, and the local time at the current location can becalculated from the time difference data and the internal time kept bythe RTC 611.

The electronic timepiece 1 in this example can also automaticallycorrect the displayed time based on the satellite signals received fromthe GPS satellites S using the reception module 50 and display controlunit 60 described above.

The power supply unit 70 includes the solar panel 25, a charging controlcircuit 71, the storage battery 24, a first regulator 72, a secondregulator 73, and a voltage detection circuit 74.

When light is incident and the solar panel 25 produces power, the powerobtained by photovoltaic generation is passed by the charging controlcircuit 71 to the storage battery 24 to charge the storage battery 24.

The storage battery 24 supplies drive power through the first regulator72 to the display control unit 60, and supplies power through the secondregulator 73 to the reception module 50.

The voltage detection circuit 74 monitors the voltage output of thestorage battery 24, and outputs to the control unit 61. The control unit61 can therefore know the voltage of the storage battery 24 and controlthe reception process.

Operating Effect

Because the shortest distance D1 from the antenna electrode 42 of theplanar antenna 40 to the metal main case 11 of the electronic timepiece1 is greater than the shortest distance D2 from the antenna electrode 42to the magnetic shield 91, the antenna electrode 42 and metal main case11 can be separated a relatively great distance. Because the metal maincase 11 is thick in the direction through the thickness of thetimepiece, the main case 11 has the greatest effect of all metal partson the reception sensitivity of the planar antenna. Therefore, if theantenna electrode 42 can be separated from the main case 11, the drop inthe reception sensitivity of the planar antenna 40 can be suppressedwhen a magnetic shield 91 and planar antenna 40 are housed inside themain case 11.

Furthermore, because the distance between the antenna electrode 42 andmain case 11 can be increased, the top edge of the metal main case 11,that is, the top of the bezel 112, can be located closer to the top ofthe timepiece (crystal 31 side) than the antenna electrode 42. Morespecifically, because metal parts that are closer to the timepiecesurface than the antenna electrode 42 affect reception sensitivity, themain case 11 must be made of plastic or other material that does notaffect reception sensitivity when the distance between the antennaelectrode 42 and main case 11 is short considering the directivity ofthe planar antenna 40. This embodiment, however, enables using a metalmain case 11, and using metal for the outside case member 111 and bezel112 of the main case 11. An electronic timepiece 1 can therefore bemanufactured with a metal case, and the appearance can be improved,including imparting a luxury appearance to the timepiece design.Furthermore, because a metal case 10 has greater durability than aplastic case, the surface is more resistance to scratching and themovement 20 inside can be better protected.

Because the shortest distance D1 from the antenna electrode 42 to themain case 11 of the electronic timepiece 1 is greater than the shortestdistance D4 from the antenna electrode 42 to the electrode of the solarpanel 25, the effect of the main case 11 on reception sensitivity can bereduced.

Therefore, a drop in the reception sensitivity of the planar antenna 40can be suppressed when a magnetic shield 91, solar panel 25, and planarantenna 40 are inside the main case 11.

Furthermore, because the shortest distance D2 from the antenna electrode42 to the magnetic shield 91 in the electronic timepiece 1 is greaterthe shortest distance D4 from the antenna electrode 42 to the electrodeof the solar panel 25, the effect of the magnetic shield 91 on receptionsensitivity can be reduced. The magnetic shield 91 is thicker than theelectrode of the solar panel 25, and has a greater effect than theelectrode of the solar panel 25 on loss of planar antenna 40sensitivity. Therefore, if the antenna electrode 42 is located furtherfrom the magnetic shield 91 than the electrode of the solar panel 25,the effect of the magnetic shield 91 can be reduced and loss of planarantenna 40 sensitivity can be suppressed.

Because the planar antenna 40 can be disposed without overlapping thestepper motors 221 to 224 and storage battery 24 in plan view, theplanar antenna 40 can be stacked on a dielectric substrate 41. As aresult, good reception performance can be assured using a planar antenna40 with a small planar size enabling incorporation in a wristwatch sizeelectronic timepiece 1. Furthermore, while the planar antenna 40overlaps the dial 2 of the time display unit 9A in plan view, thereception performance of the planar antenna 40 can be assured becausethe dial 2 is made from a non-conductive material. The effect of thehands 3 on reception performance can also be minimized even if the hands3 are made of a conductive material because the plane area of the handsis small.

Reception performance can therefore be assured, and a thin electronictimepiece suitable as a wristwatch can be provided.

Because the winding stem, setting lever, and other switching mechanismsare located at 3:00 on the dial 2 in plan view, the plane area of theelectronic timepiece 1 must be increased if the planar antenna 40 orstorage battery 24, which are relatively large compared with othertimepiece parts, is disposed to the 3:00 position. Because the planarantenna 40 and storage battery 24 are not disposed at 3:00 in thisembodiment, the plane size of the electronic timepiece 1 can be reducedwithout interfering with the layout of switching members disposed at3:00.

Furthermore, because the storage battery 24 is located in a notch 231 inthe circuit board 23, the thickness of the electronic timepiece 1 can bereduced compared with a configuration having the battery on the backside of the circuit board 23, and a thin electronic timepiece 1 can beprovided.

The appearance of the electronic timepiece 1 can also be improvedbecause part of the case 10, such as the outside case member 111, bezel112, and back cover 12, can be metal. Furthermore, because the ringmembers including the dial ring 32 disposed around the outsidecircumference of the dial 2 are made from non-conductive materials, theplanar antenna 40 can receive satellite signals passing from the crystal31 side of the timepiece through the dial 2, dial ring 32, and baseplate 21, and good reception performance can be assured even though theoutside case member 111, bezel 112, and back cover 12 are metal.

Furthermore, because the subdial 2A is disposed to a position notoverlapping the planar antenna 40 in plan view, metal parts can be usedfor the markers of the subdial 2A, for example, and the design can beimproved.

Furthermore, because a shock absorber 47 is placed between the coverpart 215 of the base plate 21 and the exposed surface 411 of thedielectric substrate 41, and the exposed surface 411 of the planarantenna 40 is set against the shock absorber 47, the planar antenna 40can be precisely positioned in the thickness (height) direction of theelectronic timepiece 1. As a result, the positioning precision of theplanar antenna 40 to the base plate 21 can be improved, change in theantenna frequency due to deviation in positioning precision can befurther reduced, and antenna performance can be further stabilized.

Furthermore, because the exposed surface 411 of the planar antenna 40contacts the shock absorber 47, direct contact with the cover part 215can be prevented, and damage to the ceramic dielectric substrate 41 canbe prevented.

Furthermore, because the date wheel 5 is made from a non-conductivematerial, a drop in reception performance can be prevented even if thedate wheel 5 overlaps the planar antenna 40 in part in plan view becausethe satellite signals can pass through the date wheel 5 to the antenna.

Furthermore, because the date wheel 5 overlaps the planar antenna 40 inplan view, there is greater freedom positioning the center pivot 3A andpivot 4A of the hands 3 and small hand 4 to avoid the date wheel 5 andplanar antenna 40, and the electronic timepiece 1 can be designed with agreater degree of freedom.

Furthermore, because the planar antenna 40 does not overlap the solarpanel 25 or magnetic shields 91, 92 in plan view, satellite signalspassing from the face side of the timepiece are incident to the planarantenna 40 without being obstructed by the solar panel 25 or magneticshield 91. A solar panel 25 and magnetic shield 91 can therefore be usedin the electronic timepiece 1 without reducing reception performance.

Because the planar antenna 40 does not overlap the main case 11 (outsidecase member 111 and bezel 112) in plan view when seen from the face ofthe timepiece, satellite signals pass from the face side of thetimepiece through the crystal 31 and are incident to the planar antenna40 without interference from the main case 11. Metal or other conductivematerial can therefore be used for the main case 11 and back cover 12without reducing reception performance, and the apparent quality of theelectronic timepiece 1 can be improved.

Furthermore, because the bezel 112 is made from a conductive material,the bezel 112 can be manufactured more easily than when using ceramic,freedom of design can therefore be improved, and cost can be reduced.Furthermore, because the bezel 112 is metal, greater rigidity can beachieved in a smaller sectional area than with a ceramic bezel. Thesectional width of the ring-shaped bezel 112 can therefore be reduced,the planar size of the crystal 31 can be increased, and the freedom oftimepiece design can be improved.

The outside case member 111 and back cover 12 can also function as aground plane because they are connected to the ground of the receptionmodule 50. The surface area of the ground plane can therefore beincreased, antenna gain improved, and antenna performance improved.

Embodiment 2

A second embodiment is described next with reference to FIG. 12. Notethat like parts in the second embodiment and the first embodiment areidentified by like reference numerals, and further description thereofis omitted.

The case 10A of an electronic timepiece 1A according to a secondembodiment uses a metal main case 11A with the outside case member 111Aand bezel 112A formed in unison. To increase the shortest distancebetween the antenna electrode 42 of the planar antenna 40 and the insidesurface of the case 10A, a portion of the inside surface of the case 10Ais removed only in the area near the planar antenna 40. As a result, thethickness of the main case 11A close to the planar antenna 40 on theright side in the figure is thinner than the thickness of the main case11A on the left side in the figure. Note that other parts are the sameas in the first embodiment, and further description thereof is omitted.

Because the outside case member 111A and bezel 112A are formed in unisonin the electronic timepiece 1A according to the second embodiment, thenumber of parts in the electronic timepiece 1A can be reduced and thecost can be reduced.

Furthermore, shortest distance D1 can be increased because the insidesurface of the case 10A is removed in the area near the planar antenna40. The planar antenna 40 can therefore be further separated from themain case 11A, the reception sensitivity of the planar antenna 40 can beimproved, and satellite signal reception performance can be improved.

Embodiment 3

A third embodiment is described next with reference to FIG. 13. Itshould be noted that identical or similar parts in this and the firstembodiment are identified by like reference numerals, and furtherdescription thereof is omitted below.

The electronic timepiece 1B according to the third embodiment uses astorage battery 24B with a smaller plane area than the storage battery24 in the first embodiment. More specifically, the diameter of thestorage battery 24 in the first embodiment is greater than the radius ofthe base plate 21 of the movement 20 as shown in FIG. 2 to FIG. 5. Thediameter of the storage battery 24B in the third embodiment is smallerthan the radius of the base plate 21 of the movement 20 as shown in FIG.13.

As a result, while the storage battery 24 in the first embodiment is alithium coin battery 20 mm in diameter and 1.6 mm thick, the storagebattery 24B of the third embodiment is a lithium battery 9 mm indiameter and 3.7 mm thick.

The electronic timepiece 1B uses a storage battery 24B with a smallplane area, and the storage battery 24B is disposed where it is notsuperimposed with the planar antenna 40, the stepper motors 221 to 224,or the wheel train.

The circuit board 23B is a single board, and the reception module 50(GPS chip) and control unit 61 (timepiece control chip) are mounted onthe single circuit board 23B. The reception module 50 is on the backside of the circuit board 23B, and is surrounded by a shield 26.

The electronic timepiece 1B also has magnetic shields 91, 92. Note thatmagnetic shield 92 is not shown in FIG. 13, but is disposed to the backcover 12 side of the wheel train bridge 27 as in the electronictimepiece 1 of the first embodiment.

As a result, the shortest distances D1 to D5 between the dielectricsubstrate 41 and the case 10, magnetic shield 91, magnetic shield 92,electrode of the solar panel 25, and storage battery 24B, respectively,is D5>D1>D3>D2>D4 as in the first embodiment.

The notch 231B in the circuit board 23B of the electronic timepiece 1Baccording to the third embodiment can be smaller than in the firstembodiment by using a small diameter storage battery 24B. As a result,the area of the circuit board 23B is greater than the foregoing circuitboard 23, there is greater freedom of design in the wiring pattern, andan ideal pattern can be designed. In addition, because the ground areaof the circuit board 23B also increases, the reception performance ofthe planar antenna 40 can be improved.

Furthermore, because the plane area of the storage battery 24B is small,the planar antenna 40, first stepper motor 221 to fourth stepper motor224, and the first wheel train 226 to fourth wheel train can be arrangedin the movement 20 without overlapping in plan view.

A storage battery 24B with a small diameter can also be disposedseparated from the planar antenna 40. As a result, the storage battery24B can be located to a position separated from the feed pin, and itseffect on reception sensitivity can be suppressed.

Furthermore, while the thickness of a high output storage battery suchas a lithium ion coin battery increases with age, because the storagebattery 24B is not superimposed with the wheel train and other parts inplan view, an increase in battery thickness does not affect theoperation of other parts.

Embodiment 4

A fourth embodiment is described next with reference to FIG. 14 to FIG.18. It should be noted that identical or similar parts in this and theforegoings embodiment are identified by like reference numerals, andfurther description thereof is omitted below.

As shown in FIG. 14, an electronic timepiece 1C according to the fourthembodiment has a dial 702 with three windows (subdials). As in theforegoing embodiments, a center pivot 3A is disposed in the plane centerof the dial 702, and a second hand 3B, minute hand 3C, and hour hand 3Dare mounted on the center pivot 3A. A round first window 770 and hand771 are disposed at 2:00; a second window 780 and hand 781 are disposedat 10:00; a third window 790 and hand 791 are disposed at 6:00; and arectangular date window 2B at 4:00. A date wheel 5 is located on theback side of the dial 702, and the date wheel 5 can be seen through thedate window 2B.

In this embodiment the hand 771 of the first window 770 is a chronographminute hand, and the hand 781 of the second window 780 is a chronograph1/5 second hand. The hand 791 of the third window 790 is used as both amode indicator and a chronograph hour hand. When used as a modeindicator, the hand 791 indicates particular settings in differentmodes, including the summer time setting (DST=daylight saving time,O=standard time (DST is off)); is used as a power indicator indicatingthe reserve power of the storage battery 24B; indicates if the in-flightmode is enabled; and indicates whether the timekeeping mode forreceiving GPS time information and adjusting the internal time, or thepositioning mode for receiving GPS time information and orbitinformation and correcting the internal time and time zone setting, isactive.

As shown in FIG. 14, the planar antenna 40, which is a patch antenna, inthis electronic timepiece 1C is between the center pivot 3A and case 10,and from 4:00 to 5:00 on the dial 702. As a result, the planar antenna40 and date window 2B do not overlap in plan view.

Note that the planar antenna 40 partially overlaps the first window 770and third window 790. As a result, to improve the reception sensitivityof the planar antenna 40, the first window 770 and third window 790 arepreferably made of plastic or other non-conductive material instead ofmetal. Metal parts can be used for the second window 780 not overlappingthe planar antenna 40 in plan view, but plastic or other non-conductivematerial is preferably used to unify the appearance with the other firstwindow 770 and third window 790.

This electronic timepiece 1C also uses the same storage battery 24B witha small plane area that is used in the third embodiment described above.In a plan view of the electronic timepiece 1C, the storage battery 24Bis preferably located at 12:00 on the dial, that is, in the area from11:00 through 12:00 to 1:00.

FIG. 15 is a basic plan view of the movement 720. The movement 720 has abase plate 721, and a drive module 722 is disposed to the base plate721. As in the foregoing embodiments, the drive module 722 includes astepper motor 221 and first wheel train 226 for driving the hands 3(FIG. 16); a second stepper motor 222 and second wheel train (not shownin the figure) for driving the minute hand 3C; a third stepper motor 223and third wheel train (not shown in the figure) for driving the hourhand 3D; and a fourth stepper motor 224 and fourth wheel train (notshown in the figure) that are used to drive both hand 791 and the datewheel 5. The fourth wheel train has a date indicator driving wheel 228(FIG. 18) for turning the date wheel 5.

The movement 720 of this electronic timepiece 1C also includes a fifthstepper motor 225 and fifth wheel train (not shown in the figure), and asixth stepper motor 227 and sixth wheel train (not shown in the figure)for driving hand 781.

The stepper motors 221 to 225, 227 are disposed to positions notsuperimposed in plan view with the planar antenna 40 and storage battery24B. More specifically, in relation to the center pivot 3A in the planecenter of the base plate 721, the stepper motor 221 is at approximately10:00, the second stepper motor 222 is at approximately 7:00, and thethird stepper motor 223 is at approximately 2:00.

The fourth stepper motor 224 is at approximately 7:00 relative to thecenter pivot 3A, and is closer to the outside circumference of thetimepiece than the second stepper motor 222 at a position overlappingthe date wheel 5 in plan view.

The fifth stepper motor 225 is between 1:00 and 2:00 relative to thecenter pivot 3A, and is closer to the outside circumference of thetimepiece than the third stepper motor 223 at a position overlapping thedate wheel 5 in plan view.

The sixth stepper motor 227 is between approximately 10:00 and 11:00from the center pivot 3A, and is closer to the outside circumference ofthe timepiece than the stepper motor 221 at a position overlapping thedate wheel 5 in plan view.

Of the center hands, that is, the second hand 3B, minute hand 3C, andhour hand 3D, the second hand 3B is longest, the hour hand 3D isshortest, and the movement period (drive period) of the second hand 3Bis shortest and the hour hand 3D is longest. As a result, the steppermotor 221 is preferably a motor with the greatest output torque, thatis, is the largest motor. Because the output torque of the third steppermotor 223 may be less than the other stepper motors 221, 222, the thirdstepper motor 223 may also be smaller. As a result, the third steppermotor 223 is located in the electronic timepiece 1C near 2:00, which isbetween the storage battery 24B and the planar antenna 40 where space isdifficult to create around the center pivot 3A, and the stepper motors221, 222 are placed in the area from 7:00 to 10:00 where a large spaceis available.

The pivot 4B to which hand 771 is attached is on the outsidecircumference side of the third stepper motor 223 and on the insidecircumference side of the date wheel 5. The hand 4C to which hand 781 isattached is on the outside circumference side of the first stepper motor221 and on the inside circumference side of the date wheel 5. The hand4D to which hand 791 is attached is near the second stepper motor 222 onthe inside circumference side of the date wheel 5.

Also in the movement 720, the winding stem 706 that connects to thecrown 6 is at 3:00 on the dial 702 in plan view, and the setting leveror other switching mechanisms (selector mechanisms), are arranged aroundthe winding stem 706.

The internal structures inside the case 10 of the electronic timepiece1C are described next in detail with reference to FIG. 16 to FIG. 18.FIG. 16 is a section view on a line through 4:00 and 10:00 on the dial702, and FIG. 17 is, like FIG. 3, a section view on a line through 12:00and 6:00 on the dial 702. FIG. 18 is a partially exploded oblique viewlike FIG. 4. Note that like parts in this and the foregoing embodimentsare identified by like reference numerals in FIG. 16 to FIG. 18.

As shown in FIG. 16 and FIG. 17, a dial 702, movement 720, planarantenna 40 (patch antenna), date wheel 5, and dial ring 32 are housedinside the case 10.

The movement 720 includes a base plate 721, a wheel train bridge (notshown in the figure), a drive module 722 supported by the base plate 721and wheel train bridge, a first circuit board 723, a second circuitboard 724, the storage battery 24B, a solar panel 25C, and a firstmagnetic shield 91C, and a second magnetic shield 92C.

As shown in FIG. 18, the solar panel 25C is on the back side of the dial702.

The solar panel 25C is similar to the solar panel 25 in the foregoingembodiments, but in this embodiment is divided into eight solar cellsconnected in series. As in the above embodiments, each solar cell hassubstantially the same generating capacity. Therefore, if one solar cellproduces approximately 0.6 V or more, the solar panel 25 producesapproximately 0.6 V×8=approximately 4.8 V or more

by connecting the eight solar cells in series.

A notch 251 is formed in the solar panel 25C at the positionsuperimposed with the planar antenna 40 in plan view, and holes 253,257, 258, 259 through which the pivots 3A, 4B, 4C, 4D of the hands passare also formed. Note that because the date window 2B is superimposedwith the notch 251 in plan view, there is no need to provide a hole inthe solar panel 25C corresponding to opening 252 in the solar panel 25described above.

The first magnetic shield 91C is disposed on the back side of the solarpanel 25C above (on the dial 702 side of) the stepper motors 221-225,227 of the drive module 722. The first magnetic shield 91C has a notch915C cut out in the area overlapping the planar antenna 40 in plan view.This notch 915C is larger than the notch 925 in the second magneticshield 92C, and is larger than the notch 915 in the magnetic shield 91in the foregoing embodiments. As a result, the notch 915C is alsosuperimposed with the date window 2B and the hole 259 through which thehand 4D passes. Apertures 913, 917, 918 through which the pivots 3A, 4B,4C pass are also formed in the first magnetic shield 91C.

The date wheel 5 is located on the back side of the first magneticshield 91C. The date wheel 5 can be seen in the date window 2B throughthe notch 915C and the notch 251.

The base plate 721 is on the back side of the date wheel 5. As in thebase plate 21 in the embodiments described above, a drive module housing21A (FIG. 16, FIG. 17), date wheel housing 21B (FIG. 18), and antennahousing 21C (FIG. 16) are disposed to the base plate 721.

The placement of the planar antenna 40 in the antenna housing 21C, andthe configuration of the planar antenna 40, are the same as in thepreceding embodiments, and further description thereof is omitted.

A wheel train bridge not shown in the figures is disposed on the backside of the base plate 721. The wheel train bridge has a bridge for eachwheel train, and is disposed appropriately to the locations of the wheeltrains.

The first circuit board 723 (not shown in FIG. 18) and the secondmagnetic shield 92C are disposed to the back side of the wheel trainbridge.

The first circuit board 723 includes lines having continuity with thecoils of the stepper motors 221-225, 227 and is connected to the secondcircuit board 724 through a connector 751. Two connectors 751 forconductivity to both ends of the coil are disposed to one stepper motor.Because there are six stepper motors in this embodiment, holes (notshown in the figure) accommodating the connectors 751 are formed in thesecond magnetic shield 92C.

A notch 925 is formed in the second magnetic shield 92C to avoidinterference with the planar antenna 40. The areas of the first circuitboard 723 and second magnetic shield 92C corresponding to the coils ofthe stepper motors 221-225, 227 are also removed, forming appropriateapertures. For example, as shown in FIG. 18, six holes 926 in which thecoils are disposed are formed in the second magnetic shield 92C.

The coils of the stepper motors 221-225, 227, the first circuit board723, and the second magnetic shield 92C therefore do not overlap in planview, and the thickness of the movement 720 can be reduced by placingthe coils in the holes 926.

The first circuit board 723 and second magnetic shield 92C are alsodisposed to not interfere with the storage battery 24B. As a result, asshown in FIG. 18, a notch 927 that is round in plan view is formed inthe second magnetic shield 92C.

The second circuit board 724 is disposed to the back of the secondmagnetic shield 92C with a spacer 750 (not shown in FIG. 18)therebetween.

As shown in FIG. 18, a substantially round notch 731 in which thestorage battery 24B is disposed and which is basically round in planview is formed in the second circuit board 724. By placing the storagebattery 24B in the notch 731, the thickness of the electronic timepiece1C can be reduced. The planar antenna 40 (patch antenna) is disposed onthe dial side of the second circuit board 724. Also disposed to the dialside of the second circuit board 724 are the reception module 50(receiver chip, GPS module) that processes satellite signals receivedfrom GPS satellites, semiconductor chip 761, the control chip (timepiececontrol chip 61) that controls driving the motors, a power supply chip75, and a memory chip (not shown in the figure).

The spacer 750 protects the IC chips. The chips are disposed atpositions at least not directly below the pivots 3A, 4B, 4C, 4D. Thesecond circuit board 724 is therefore disposed below the pivots 3A, 4B,4C, 4D with the spacer 750 therebetween and no semiconductor chips ordevices directly below the pivots 3A, 4B, 4C, 4D. A circuit cover 725 isalso disposed on the back side of the second circuit board 724.

As a result, the force of pushing the hands 3 (second hand 3B, minutehand 3C, hour hand 3D), and hands 771, 781, 791 onto the pivots 3A, 4B,4C, 4D is borne by the circuit cover 725 through the wheel train bridge,first circuit board 723, second magnetic shield 92C, spacer 750, andsecond circuit board 724.

A back cover lead spring 725A for conductivity to the back cover 12 isformed in unison with the circuit cover 725. Plural back cover leadsprings 725A are disposed to the circuit cover 725.

A battery terminal connector 740 is disposed to the back cover side ofthe storage battery 24B as shown in FIG. 17, and the battery terminalconnector 740 is conductive to the second circuit board 724. While notshown in the figures, the solar panel 25C is conductive to the secondcircuit board 724, and is configured so that power produced by the solarpanel 25C can charge the storage battery 24B through the second circuitboard 724.

Also in this electronic timepiece 1C, as shown in FIG. 16, the shortestdistance between the antenna electrode 42 of the planar antenna 40 andmain case 11 is D1; the shortest distance between the antenna electrode42 and the first magnetic shield 91C disposed on the back of the dial702 is D2; and the shortest distance to the second magnetic shield 92Con the back side of the first circuit board 723 is D3.

As described above, because the planar antenna 40 has strong directivitytoward the zenith (the direction toward the crystal 31), the receptionsensitivity of the planar antenna 40 is easily affected by the case 10,which is the thickest of the metal parts and is located closer to theface of the timepiece than the planar antenna 40. As a result, theshortest distance D1 between the antenna electrode 42 of the planarantenna 40 and the case 10 must be increased to sufficiently separatethe antenna electrode 42 from the case 10.

Because the first magnetic shield 91C and the second magnetic shield 92Care metal, they absorb radio waves and interfere with reception by theplanar antenna 40. As a result, reception performance can be improved byseparating the first magnetic shield 91C and second magnetic shield 92Cfrom the planar antenna 40. However, to improve the magnetic resistanceof the electronic timepiece 1C, the first magnetic shield 91C and secondmagnetic shield 92C preferably cover the largest possible area.

Comparing the first magnetic shield 91C and the second magnetic shield92C, the first magnetic shield 91C located on the crystal 31 side of theantenna electrode 42 has a greater effect on reception. As a result, bymaking the area of the notch 915C in the first magnetic shield 91Clarger than the notch 925 in the second magnetic shield 92C, theshortest distance D2 between the antenna electrode 42 and the firstmagnetic shield 91C is greater than the shortest distance D3 between theantenna electrode 42 and the second magnetic shield 92C (D2>D3). In thisembodiment, therefore, D1>D2>D3.

Because the shortest distance D2 between the antenna electrode 42 andthe first magnetic shield 91C is greater than the shortest distance D3between the antenna electrode 42 and the second magnetic shield 92C inthe electronic timepiece 1C according to the fourth embodiment, a dropin reception performance can be prevented because the first magneticshield 91C that is above (on the crystal 31 side of) the antennaelectrode 42 and easily affects reception performance can be separatedfrom the antenna electrode 42. Furthermore, because the shortestdistance D3 between the antenna electrode 42 and the second magneticshield 92C located below (on the back cover 12 side of) the antennaelectrode 42 is less than shortest distance D2, the area of the secondmagnetic shield 92C can be increased and magnetic resistance can beimproved. Reception performance can therefore be balanced with magneticresistance, and a small electronic timepiece 1C can be achieved.

Furthermore, because the shortest distance D1 between the antennaelectrode 42 and case 10 is greater than the shortest distances D2, D3between the antenna electrode 42 and magnetic shields 91C, 92C, theeffect of the case 10 on reception performance can be reduced anddesirable reception performance can be assured.

Furthermore, because a small diameter storage battery 24B is used, thesame effect as the third embodiment is achieved. For example, the wiringpatterns on the first circuit board 723 and second circuit board 724 canbe designed more freely and an ideal pattern can be designed. As aresult, the six stepper motors 221-225, 227 can be desirably arranged,and a multi-hand, multifunction timepiece capable of independentlydriving all of the hands 3 (second hand 3B, minute hand 3C, hour hand3D), 771, 781, 791 can be easily produced.

Furthermore, because the ground area of the second circuit board 724also increases, the reception performance of the planar antenna 40 canbe improved. The storage battery 24B, planar antenna 40, stepper motors221-225, 227, and wheel trains can also be arranged without overlappingin plan view, and a thin electronic timepiece 1C can be achieved.

The circuit board includes two parts, a first circuit board 723 and asecond circuit board 724, and the lines that connect to the coils of thestepper motors 221-225, 227 are formed on the first circuit board 723and connect to the second circuit board 724 populated with IC chips anddevices through a connector 751. As a result, when the number of handschanges, or the locations of the stepper motors 221-225, 227 change, thesame second circuit board 724 can still be used while replacing only thefirst circuit board 723 with a compatible circuit board. Changes in thenumber of hands and layout can therefore be easily accommodated.

Because a plastic spacer 750 shaped to not interfere with chips anddevices on the second circuit board 724 is disposed between the firstcircuit board 723 and the second circuit board 724, when the hands 3,771, 781, 791 are pushed onto the pivots 3A, 4B, 4C, 4D, the forceapplied from the pivots 3A, 4B, 4C, 4D through the wheel train to thefirst circuit board 723 and second magnetic shield 92C can be supportedthrough the spacer 750 by metal parts such as the second circuit board724 and the circuit cover 725. Compressive force from pushing the handsonto the pivots can therefore be supported by high strength metal parts,and the hands can be consistently and reliably installed.

Furthermore, because aback cover lead spring 725A rendered by processingthe circuit cover 725 has continuity with the metal back cover 12, theback cover 12 can be used as a ground, and electrostatic resistance andreception performance can be improved. More particularly, because thereare plural back cover lead springs 725A in this embodiment, the backcover 12 can be reliably used as ground, and electrostatic resistanceand reception performance can be improved.

Other Embodiments

The invention is not limited to the foregoing embodiments, and can bevaried in many ways without departing from the scope of the accompanyingclaims.

For example, as shown in FIG. 19, a metal bezel cover 112C may beaffixed to a plastic main case 11C as the outside case of the electronictimepiece. In this configuration, the bezel cover 112C is a metal partof the case. Thus comprised, the reception performance of the planarantenna 40 can be improved because the shortest distance D1 between theantenna electrode 42 and the bezel cover 112C that is the metal part ofthe case can be increased.

The configurations of the planar antenna and circuit boards are notlimited to the embodiments described above. For example, the planarantenna 40 may be formed with the antenna electrode 42 formed on thesurface of the dielectric substrate 41 offset in the direction away fromthe main case 11.

By thus disposing the antenna electrode 42 of the planar antenna 40 awayfrom the metal outside case member 111, the shortest distance D1 can beincreased, and signal blocking effect of the metal outside case member111 can be reduced.

In the embodiments described above, the shortest distance D5 between theantenna electrode 42 and the storage battery 24, 24B is set greater thanthe shortest distance D1 between the antenna electrode 42 and the maincase 11 (D1<D5) by using a flat storage battery 24 and disposing thestorage battery 24 at a different elevation than the antenna electrode42, or using a small diameter storage battery 24B to separate thestorage battery 24B from the antenna electrode 42 in the planedirection, but depending on the arrangement of the storage battery 24,24B, configurations in which D1>D5 are also conceivable. In this event,because the antenna electrode 42 of the planar antenna 40 can beseparated from the metal case members (main case 11), the effect of themetal case 10 on reception performance can be reduced. The storagebattery 24, 24B is thinner than the case 10, and the location of thebattery in the thickness direction of the timepiece is generally closerto the back cover 12 than the antenna electrode 42. As a result, theeffect of the battery on the reception performance of the planar antenna40 is less than the case 10. Therefore, if the antenna electrode 42 ofthe planar antenna 40 is separated from the case 10 more than thestorage battery 24, 24B so that D1>D5, suppressing a drop in thesensitivity of the planar antenna is easier than if D1<D5.

The bezel 112 in the foregoing embodiments is made from a conductivematerial, but the invention is not so limited. For example, the bezel112 may be made from a non-conductive material such as zirconia (ZrO2)or other ceramic. Zirconia not only has high resistivity and no adverseaffect on signal reception, it is also hard with excellent scratchresistance, and is outstanding as an external member of a timepiece.Furthermore, if the bezel 112 is ceramic, the bezel 112 may besuperimposed with the antenna electrode 42 in plan view. As a result,because the diameter of the outside case member 111 need not beincreased so that the bezel 112 does not overlap the antenna electrode42 in plan view, the diameter of the outside case member 111 can bereduced and a electronic timepiece 1 with a small plane area can beprovided.

The electronic timepiece 1 in the foregoing embodiments has a date wheel5, solar panel 25, and dial ring 32, but the invention is not solimited. More specifically, the electronic timepiece may be configuredwithout a date wheel 5, solar panel 25, or dial ring 32.

The outside case member 111 and back cover 12 are connected to theground part of the reception module 50 in the embodiments describedabove, but the invention is not so limited. More specifically, theoutside case member 111 and back cover 12 do not need to be connected tothe ground of the reception module 50.

The solar panel 25 in the foregoing embodiments has a notch 251 in thearea superimposed with the planar antenna 40 in plan view, but the solarpanel 25 is not limited to having a notch 251. The solar panel 25 simplyneeds to be configured so that it does not affect signal reception bythe planar antenna 40, and may simply be shaped so that the solar paneldoes not overlap the planar antenna 40 in plan view. For example, partof the solar panel 25 may be removed to form an opening only where thesolar panel 25 would overlap the planar antenna 40 in plan view, or thesolar panel 25 may be formed in a semicircle and placed so that thesolar panel does not overlap the planar antenna 40 in plan view.

The first magnetic shield 91, 91C and second magnetic shield 92, 92C arecut away to form the notches 915, 915C, 925, but the first magneticshield and second magnetic shield are not limited to forms having anotch. More specifically, the first magnetic shield and second magneticshield may be desirably shaped to achieve an appropriate distance to theplanar antenna 40 considering the effect on reception.

The foregoing embodiments are described with reference to a GPSsatellite S as an example of a positioning information satellite, butthe invention is not limited to GPS satellites and can be used withGlobal Navigation Satellite Systems (GNSS) such as Galileo (EU), GLONASS(Russia), and Beidou (China). The invention can also be used withgeostationary satellites in satellite-based augmentation systems (SBAS),and quasi-zenith satellites in radio navigation satellite systems (RNSS)that can only search in specific regions.

The invention being thus described, it will be obvious that it may bevaried in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

The entire disclosures of Japanese Patent Application Nos. 2015-156169,filed Aug. 6, 2015 and 2016-023812, filed Feb. 10, 2016 are expresslyincorporated by reference herein.

What is claimed is:
 1. An electronic timepiece comprising: a case ofwhich at least part is metal; a hand and a movement disposed inside thecase; the movement including a circuit board, a planar antenna includingan antenna electrode and being attached to the circuit board, a motorconfigured to drive the hand, and a magnetic shield superimposed in planview with at least a part of a body of the motor, and not superimposedin plan view with the planar antenna, the magnetic shield including afirst magnetic plate and a second magnetic plate, the first magneticplate being disposed on a face side of the motor and the second magneticplate being disposed on a back cover side of the motor; and the shortestdistance between the antenna electrode of the planar antenna and themetal part of the case being greater than the shortest distance betweenthe antenna electrode and the first magnetic plate or the secondmagnetic plate.
 2. The electronic timepiece described in claim 1,wherein: the top of the metal part of the case at the end on the faceside of the timepiece is above the antenna electrode on the face side ofthe timepiece.
 3. The electronic timepiece described in claim 1, furthercomprising: a solar panel not superimposed with the antenna electrode inplan view, the shortest distance between the antenna electrode and themetal part of the case being greater than the shortest distance betweenthe antenna electrode and an electrode of the solar panel.
 4. Theelectronic timepiece described in claim 1, further comprising: a batterynot superimposed with the planar antenna in plan view, the shortestdistance between the antenna electrode and the metal part of the casebeing greater than the shortest distance between the antenna electrodeand the battery.
 5. The electronic timepiece described in claim 1,wherein: the shortest distance between the antenna electrode and thefirst magnetic plate is greater than the shortest distance between theantenna electrode and the second magnetic plate.
 6. An electronictimepiece comprising: a case of which at least part is metal; and a handand a movement disposed inside the case, wherein the movement includes:a circuit board, a planar antenna including an antenna electrode andbeing attached to the circuit board, a motor configured to drive thehand, and a magnetic shield superimposed in plan view with at least apart of a body of the motor, and not superimposed in plan view with theplanar antenna, the shortest distance between the antenna electrode ofthe planar antenna and the metal part of the case is greater than theshortest distance between the antenna electrode and the magnetic shield,and the shortest distance between the antenna electrode and the magneticshield is greater than the shortest distance between the antennaelectrode and the electrode of the solar panel.